As visualization and the tendency of multimedia have progressed in recent years, the needs for high quality, such as visualization or color, of printed matters having been widely used as media of publication, advertisement, and publicity have been rapidly increased. The change of the demands for uncoated printing paper in the related art to coated printing paper has been increased in accordance with these changes of user's needs, so that the demands for the coated printing paper has been rapidly increased.
In addition, since printing has been performed on the front and back surfaces of the coated printing paper in the past, there have been demands for coated paper that has the same quality, such as, glossiness, smoothness, and whiteness, on the front and back surfaces thereof. On the other hand, there has been also increased needs for separately using the front and back surfaces where designs having high visual quality are printed using four colors on the front surface of a published matter or throwaway and subsidiary designs are printed only using one or two colors on the back surface thereof in order to reduce cost.
In addition, requests for qualities of handling ability of printing paper and running stability on a printing machine, which correspond to improvement of workability or efficiency in a printing process, have become hard to be satisfied.
In response to the requests for qualities, the width and operating speed of a paper machine have been increased in the paper making industry for the purpose of labor saving and the reduction of manufacturing cost.
There are tendencies of the reduction of the metric weight of base paper, bipolar division between fine coating paper and coated paper having a large amount of a coating material, and differentiation of qualities on the front and back surfaces in coping with a request for quality of coated paper, labor saving, and reduction of manufacturing cost. Thus, there has been strongly required, in a manufacturing site, the development of manufacturing technique of coated paper which can satisfy the demand for the manufacture of the above-mentioned various kinds of coated paper taking an advantage of property for high speed operation.
Japanese Unexamined Patent Publication (Kokai) No. 05-51898 discloses a method of manufacturing multilayer coated paper that includes at least one or more overcoating layers formed on a support on which an undercoating layer is formed. In the method, the one or more overcoating layers are formed by blade coating and a surface treatment is performed on the surface of a coating layer by rigid surface-roughening roll before the blade coating is performed so that the surface of the coating layer has a surface roughness (Rmax) in the range of 8 to 30 μm defined in JIS B 0651. This document discloses as follows: a size press coater, a bar coater, an air knife coater, a roll coater, a rod blade coater, a doctor blade coater, and the like are used as a coating device in the method of manufacturing coated paper that coats the base paper with a coating solution containing a pigment and an adhesive as main ingredients, dries the paper, and finishes the paper. One coater, several same coaters, or different coaters of these coating devices are appropriately combined and used according to the quality design of a final product, the intended purpose of the product, and the use thereof so as to perform single-layer coating or multilayer coating.
However, coating facilities capable of being used to manufacture the coated paper are merely enumerated, which is the modification of the related art. Even though various coating facilities are used, the selective combination and arrangement of the coating facilities, and the cooperation with other facilities are not described and suggested. Further, since operability and productivity are not improved in a coated paper manufacturing site on a so-called on-machine where various kinds of coated paper are produced by a paper machine for consistently performing a papermaking process, a coating process, and a flattening process, a fundamental countermeasure is not obtained.
Accordingly, as a method to solve the above-mentioned problems, the present applicant has already proposed a method of manufacture coated paper through the combination of a roll coater coating facility and a blade coater coating facility in Japanese Patent Application No. 2005-179111 (published in Japanese Unexamined Patent Publication (Kokai) 2007-31925).
According to Japanese Patent Application No. 2005-179111 (published in Japanese Unexamined Patent Publication (Kokai) 2007-31925) various kinds of coated paper could be easily manufactured through the selectively use of the roll coater coating facility and the blade coater coating facility. In this case, before coated paper reaches a flattening facility from a roll coater coating facility, the moisture percentage of the coated paper needs to be in a predetermined range. However, if a blade coater coating facility for forming a coating layer on the surface of the base paper and a blade coater coating facility for forming a coating layer on the back surface of the base paper are provided in a post-process of the roll coater coating facility, a distance gets longer between the roll coater coating facility where the coating layer is formed and the flattening facility where the paper is fed from the coating facility. Accordingly, it may be difficult to make the moisture percentage of the coated paper be in a predetermined range. For this reason, the reduction of an ununiformed coating layer in a flattening treatment performed by the flattening facility has been required, and the contamination of a feeding line and a paper break trouble caused by contamination have been required to be suppressed.